I. Field of the Invention
This invention relates to a system for image processing an interlaced digital video input signal and, more particularly, to such a system incorporating filter apparatus comprised of one or more multitap digital filter/decimators and/or expander/interpolation filters suitable for image processing, in real time, two-dimensional images, such as television images, employing an interlaced scanning raster.
II. Description of the Prior Art
Reference is made to co-pending U.S. patent application Ser. No. 596,817, filed Apr. 4, 1984 by Carlson et al., and assigned to the same assignee as the present application. This co-pending Carlson et al. application discloses real-time hierarchal pyramid signal processing apparatus which employs pipe-line architecture for analyzing in delayed real time, inter alia, the two-dimensional spatial frequency spectrum of television images defined by a temporal video signal, and for synthesizing in delayed real time such a temporal video signal from the analyzed frequency spectrum thereof. In particular, the signal processing apparatus disclosed in this co-pending Carlson et al. application is capable of implementing an algorithm, developed by Dr. Peter J. Burt (hereinafter referred to as the "Burt Pyramid") by means which include many digital convolution filters, decimators, expanders, and interpolation filters, all operating on a stream of multibit (e.g., 8-bit) digital signal samples. In the past, the total amount of hardware required for the structure of such digital convolution filters, decimators, expanders and interpolation filters was quite large and, hence, relatively expensive.
Reference is further made to pages 79-88 of the book Multirate Digital Signal Processing, by C. Rochiere et al., published by Prentice Hall, Inc., in 1983, which discusses the use of polyphase component filters for decimation and interpolation with integer changes in sampling rate.
Reference is further made to co-pending U.S. patent application Ser. No. 632,467, filed July 19, 1984, by Arbeiter, and assigned to the same assignee as the present application. This co-pending Arbeiter application discloses improved-structure input-weighted multitap digital filters that incorporate a plurality of polyphase component filters and which are suitable for use as a filter/decimator and/or an expander/interpolation filter.